Electric testing tool



Dec. 3, 1929. DlRKSEN 1,738,287

ELECTRIC TESTING TOOL Filed Aug. 3, 1927 Patented Dec. 3, 1929 CLARENCEA. DIRKSEN, OF DUBUQUE, IOWA ELECTRIC TESTING TOOL Application filedAugust 3, 1927.

The present invention relates to a tool for testing electric circuits,and aims to provide a novel and improved device of this character foruse by electricians, such as linemen and others, the said testing deviceor tool having prongs thereon for piercing the 1nsulation of conductorsin order to establish contact therewith for conveniently and efficientlylocating breaks in the conductors.

Another object of the invention is the provision of an electric testingtool arranged in the form of a pair of pliers having a removable bloclrof insulating material on one jaw thereof for detachably supporting aplurality of prongs or contact points, which may be in the form ofphonograph needles.

It is also an object of the invention to provide a device of the aboveindicated character, which is simple and substantial in construction,which can be manufactured economically, and which will be thoroughlyefficient and practical in use.

l Vith the foregoing and other objects in view, which will be apparentas the description proceeds, the invention resides in the constructionand arrangement of parts, as hereinafter described and claimed, it beingunderstood that changes can be made within the scope of what is claimed,without departin from the spirit of the invent-ion.

'lhe invention is illustrated in the accompanying drawings, wherein:

Figure 1 is a side elevation of my improved device, 1

Figure 2 is a longitudinal section taken on line 22 of Figure 1,

Figure 3 is a fragmentary longitudinal section talren'on line 3-3 ofFigure 2, and

Figure 4 is a cross section taken on line l l of Figure 3.

Referring to the drawings, the numeral 10 design ates the devicearranged in the form of a pair of pliers, having a pair of sections 11and 12 pivotally connected together, as at 18, so as to provide twohandle sections 14 and and a pair of jaws 16 and 17. The sections 11 and12 are preferably constructed in the form of channel members cut awayadjacent the point of pivot thereof so as to permit the member 11 toextend through the Serial No. 210,320.

member 12 for pivotal connection and operation after the manner ofordinary pliers.

in carrying out my invention, the jaw 16 has the face thereof cut away,as at 18, and a block of insulating material 19 is attached to said jawat said cut away portion to the side walls 20 and 21 thereof and to theconnecting portion 22 at the forward end of said side members. The block19 is positioned between the side members 20 and 21 and has its forwardend notched, as at 28, for resting on the connecting portion 22. A screw24: is passed transversely through the rear end of the block 19 and sidemember 21 being threaded into the side member 20 for attaching the rearportion of the block in a rigid manner to the jaw 16 and at the forwardend of the block a screw 25 is threaded therein through an openingtherefor in the conneeting port-ion 22 0f the aw and is provided with anelongated head 26, the purpose of this screw 25 being to permanentlyattach the forward end of the block 19 to the jaw, while the screw 24permanently attaches the rear end of the block to the jaw. The oppositesides of the block 19 are cut away, portions 27, to permit the upperfaces of the block to lie flush with the side faces of the side members20 and 21 of the jaw 16 and by cutting away the block in this manner,shoulders 28 are provided on the block which rest on the upper edges ofthe side members 20 and 21 of the jaw so as to aid in supportin theblock thereon,

Extending into the block from the lower side thereof is an enlargedrecess 30 which receives the upper ends of a plurality of pins 31 whichhave their lower ends tapered to provide sharp points, as at 32. Thepins 31 are preferably arranged in two rows and are of sutlicient lengthto project below the block 19 when the upper ends thereof are inengagement with the bottom of the recess 30. lshonograph needles havebeen found very practical for the purpose for which these pins areprovided, as they form an eflicient and inexpensive means for puncturingthe insulation and establishing contact with the electric conductor. Thephonograph needles need not be new ones, butmay be used ones which wouldordinarily be thrown away. In order that the pins 31 may be firmly heldin the recess of the block 19, a screw 33 is threaded through the frontend of the block 19 and engages the pins so as to clamp the sametogether and against the opposite end wall in order .tohold said pinsagainst accidental removal.' The screw 33 is of a size equalapproximately to the width of the recess 30 so as to firmly engage thepins at the end of the recess adjacent the screw to clamp all of saidpins between said screw and the opposite end of the recess. As shown inFigure 2 of the drawings the end wall of the recess opposite to thatthrough which the screw 33 extends and designated by numeral 34, may bearranged at an angle so that when the pins are clamped in the recess thetwo rows are arranged in staggered relation, whereby the danger. of thewire or electric conductor being tested positioning itself betweenprongs or contact-points is practically eliminated.

The'elongated head 26 on the screw 25 will abut against the jaw 17 whenthe jaws of the tool are brought together, thus preventing the sharppoints 32 on the pins 31 engaging the face of the jaw 17 which wouldtend to destroy the points on said pins.

In use, it can be seen that by placing an insulated'wire or wiresbetween the jaws 16 and 17 and forcing the handles 14 and 15 togetherthe points 32 carried by the jaw 16 will be forced through theinsulation on the wire or wires as the jaw 17 engages the opside orsidesthereof. The device will ound very efiicient for testing electriccircuits inwhich electric lights, etc., are arranged in seriestherewith. In testing electric light circuits the device may be clampedin rear of the first light and if the same flashes this will indicatethatthe light and conductors to such point are in good condition. Byproceeding on down the line in rear of each 7 light, it may be easilydetermined where the defective point is and of course in testing acircuit of this character, both wires of the circuit are clamped betweenthe jaws of the device. 7

When the points of the pins become dull and in'efiicient, the screw 32may be loosened 1nd new pins, such as phonograph needles or theilike,placed in the recess and the screw tightened in order, to clamp thembetween the screw and the opposite endof the recess. By having the block19 constructed of insulating material, it can be seen that the user ofthe device will not be subjected to electric shocks. when testing wires.Having thus described my invention, what I claim as new is:

1. 1m electric circuit tester comprising a air of members pivotallyconnected together intermediate their ends to provide jaw portions andhandle portions, a block of insulating material attached to one jaw andhaving a recess therein, a plurality of pins arranged in said recess andslightly protruding from the block, and a set screw threaded in theblock and engaging said pins so as to clamp the same between said setscrew and the opposite end of the recess.

2. An electric circuit tester comprising a pair of members pivotallyconnected together intermediate their ends to provide jaw portions andhandle portions, :1 block of insulating material having a recessarranged therein, a screw extending through one of said jaws and intothe block for attaching the block to the jaw and for limiting movementof said jaws towards each other, and a plurality of pins arranged in therecess of said block and protruding slightly from the block in thedirection of the opposite jaw.

3. An electric circuit tester comprising a pair of members pivotallyconnected together so as to provide jaws, said jaws being of channelformation in cross section, one of said jaws having a portion of thebight portion of the channel shaped portion cut away, a

block arranged in the channel of the jaw having a portion thereof cutaway, screws extending through the jaw and into the block for attachingthe block to the jaw, said block having a recess arranged thereinopening at the point where the jaw is cut away, a plurality of pinsarranged in said recess and pro truding slightly from the jaw, and a setscrew threaded in the block and engaging certain of the pins forclamping the same between said screw and the opposite end of saidrccess.

4:. An electric circuit tester comprising a pair of members pivotallyconnected together so as to provide oppositely arranged jaws, said jawsbeing of channel shaped formation in cross section, one of said jawshaving an opening through the bight portion thereof, a block ofinsulating material attached to the last mentioned jaw and having arecess registering with the aforesaid opening, screws for attaching saidblock to said jaw, said block having opposite side portions thereof cutaway so as to provide shoulders engaging the upper edges of the channelshaped jaw, a plurality of pins arranged in the recess of said block andprotruding slightly below said jaw, and a set screw threaded in saidblock and in engagement with certain of said pins for clamping all ofsaid pins in the block against the opposite end of the recess.

CLARENCE A. DIRKSEN.

